Conventionally, there is known a rotation angle detecting device with two integrated circuits (IC) packages including magnetism detecting elements respectively. In, for example, JP-A-2004-004114, there is described a rotation angle detecting device in which two IC packages are arranged side by side in a board surface direction (see FIG. 6 in JP-A-2004-004114). In this rotation angle detecting device, two magnetism detecting elements are arranged at positions away from a rotation axis of a detection object. Accordingly, by providing a stator having a magnetic collecting effect, deterioration of sensor characteristics is limited.
In the case of the above-described rotation angle detecting device, if the stator is eliminated for the purpose of cost reduction, the sensor characteristics deteriorate, and accuracy in detection of a rotation angle is reduced. In JP-A-2004-004114, it is illustrated that two IC packages are arranged side by side in a board thickness direction (see FIG. 8 in JP-A-2004-004114). By arranging the two IC packages in this manner, the sensor characteristics are good, so that the stator can be eliminated. However, in the example illustrated in FIG. 8 in JP-A-2004-004114, wires for signal output which are connected respectively to the two IC packages are disposed to be adjacent to each other. For this reason, the wires may be short-circuited, such as when conductive foreign substances are attached between the two wires for signal output. If the wires for signal output are short-circuited, signals from the two magnetism detecting elements may be mixed together to be outputted to the outside. As a result, a false detection of the rotation angle may be caused.